DOI: 10.5176/2251-3833_GHC17.43

Authors: King Chung


Abstract: The World Health Organization defines disabling hearing loss for children as having an average hearing threshold of >30 dB HL at 500, 1000, 2000, and 4000 in the better ear. In high income countries, however, a hearing loss for children is commonly defined as having an average of >20 dB HL in either ear. The purposes of this study were 1) to compare the prevalence of hearing loss in three countries using these two definitions of hearing loss, and 2) to examine the adequacy of using pure tone thresholds as an indication of hearing health care needs. A total of 1330 children in Brazil, Cambodia, and China participated in the study. Their outer, middle, and inner ear functions were assessed using otoscopy, tympanometry, and distortion-product otoacoustic emissions, respectively. If otoacoustic emissions of ≥6 signal-to-noise ratio were not present in 4 of the 6 test frequencies, a pure tone audiometry was administered. Results indicate that the WHO hearing loss criterion significantly underestimated the prevalence of hearing loss in these populations (i.e., overall = 6.7 times lower). When other ear and hearing disorders such as ear wax accumulation and middle ear problems are considered, however, the referral rate increased to 21{6e6090cdd558c53a8bc18225ef4499fead9160abd3419ad4f137e902b483c465}, 16.7{6e6090cdd558c53a8bc18225ef4499fead9160abd3419ad4f137e902b483c465}, and 10.6{6e6090cdd558c53a8bc18225ef4499fead9160abd3419ad4f137e902b483c465} in Brazil, Cambodia, and China, respectively. As children with minimal or unilateral hearing loss are negatively affected by hearing loss, hearing professionals in different countries are encouraged to adopt more stringent than WHO criteria to identify children with hearing loss and disorders. Additionally, hearing testing protocols should include the examination of outer, middle, and inner ear status, and interventions should be provided immediately following identification to minimize the negative effects of hearing loss on children’s speech, language, cognitive, and social development.

Keywords: hearing loss, disorder, prevention, identification, intervention, epidemiology, Brazil, Cambodia, China

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